A machine of this type is described in Swiss patent 683.757 and comprises a guide path on which carriers bearing a preform are moved through the various production steps and devices. The carriers and the preforms comprise a single row moving at a single speed. Given that the heating of the preforms is a relatively long operation, the length of the guide path must be fairly great to obtain suitable heating, which greatly increases the overall size of the machine, or else the speed of the preforms along the entire circuit must be lowered as a result, which considerably reduces the output of the machine.